Welcome to the second edition of “Best of the Federated Search Blog.” In this series I pull articles out of the Federated Search Blog archive and comment on them for the benefit of those considering Deep Web Technologies‘ offerings.

In March, 2008 I explored the “incremental results” feature which Deep Web Technologies makes available in all its federated search applications. As a consultant to Deep Web Technologies I may be somewhat biased but I do believe that this feature is a huge differentiator for the company.

Why is it a big deal to provide incremental results? It’s because we live in the age of Google speed. Users don’t want to wait the 30 seconds it could take a content source to provide its results. The achilles heel of federated search is the fact that we have no control over how quickly sources respond with their results. If a federated search application is searching 30 sources at once and 29 of them return results quickly but one is slow to respond then the traditional approach to displaying search results has users wait until the last source returns its results. This is bad news for the impatient user.

Deep Web Technologies’ approach is to wait just a few seconds, long enough to get a variety of documents from a number of sources. It then relevance ranks those documents and displays those results quickly to users. While users are inspecting those first results, Explorit (Deep Web Technologies’ federated search engine) is gathering results from the other sources to display when the user is ready.

Explorit is polite to users. It doesn’t simply overwrite the first set of search results with a later batch. It instead informs the users that a newer set is available and asks the user if he wants that set. The user can take the offer, turn it down or defer it (waiting until later to refresh the results.)

Incremental results are a nice way to balance the federated search speed issue with the user demand for speed. We think the feature works well. You can judge for yourself at Science.gov, WorldWideScience.org, and Scitopia.org.